Early Effects of Efferent Duct Ligation on the Rat Rete Testis

Early effects of efferent duct ligation (EDL) were studied in adult rats using histological serial sectioning and electron microscopy.
From 30 min to 3 h after EDL the rete cavities dilated and there was accumulation of sperm and cellular debris. The lumen of the transitional zone, the junction of the seminiferous tubules with the tubuli recti, opened and the Sertoli cell bodies straightened up. The direction of sperm tails in the lumen of the seminiferous tubules near the transitional zone changed suggesting a backflow from the rete towards the seminiferous tubules. These changes progressively increased until 12 h. The distensibility of various parts of the rete was unequal. Likewise, the susceptibility of the junctional zone to pressure effects was related on its structure and position. Early changes in the rete testis and the transitional zone epithelium were fully reversible and seemed to be caused by mechanical influence of flow direction only. No evidence of a valve function of the transitional zone was obtained.